Among pagers for carrying out radio communication of information, there are a numeric pager and an alphanumeric pager. The numeric pager can deal with the number only, while the alphanumeric pager can deal with alphabet, Japanese katakanas, and the number. In either case, the usage is limited to the case where the accessing is carried out to a designated person who is in a unspecified area or to the case where some messages are transmitted to a disignated person. In other words, the trasmissible information is limited to the alphabet, Japanese katakanas, and the number. Accordingly, the conventional pager has been used only for transmitting messages, i.e., the conventional pager has not been used for other usage.
When a portable information terminal such as an electronic notebook is connected with a peripheral device such as modems, the user can obtain at any time the latest information or necessary information by accessing on-line services or data base through public network from outside. However, according to the portable information terminal, the user can not know whether or not some changes such as updating is carried out with respect to a file unless the user itself checks it. The user itself must access and check the data base by use of the portable information terminal, when the user wishes to know (1) whether or not the updating is carried out with respect to the file and (2) whether or not the user's data currently available is the latest one. Namely, in order to obtain the latest information, it was necessary for the user itself (1) to frequently access the data base so as to check whether or not the file is updated, (2) to check which information is the latest one, and thereafter (3) to receive such information.
When the file has been changed and the data base has the latest file, even in the case where the number of changes in the file is not many, the user must receive the entire file. Accordingly, the communication time and the cost of the communication have been wastefully consumed. In the case of the updating, the user can not verify which part of the data has been updated.
According to the technique disclosed in Japanese unexamined patent publication No. 2-280185/1990, a time table of a portable device is periodically updated by use of the radio electric wave or the telephone line. However, according to the technique, the radio electric wave or the telephone line is used as broadcasting means, not as communication means. More concretely, a predetermined service organization delivers the time table data by use of an exclusive radio electric wave or an exclusive telephone line. When the portable device receives the data through the exclusive radio electric wave or exclusive telephone line, the portable device judges that the data thus received is the data relating to the time table, thereafter selects the necessary time table data relating to a target station from the received data and stores it. According to the technique, (1) the data to be delivered is limited to the data having a specific form, i.e., a time table data and (2) the direction of the delivery is limited to the portable device from the service organization.